1. Field of the Invention
The invention relates to hay and grass balers and, in particular, to a twine cutting knife for cutting twine used to wrap bales formed with the balers.
2. Description of the Prior Art
Ranchers and farmers grow, cut and store grass and hay in rectangular bales to feed livestock during severe winter weather when grass is dormant and livestock cannot graze (round bales may also be gathered using different machinery). This process is performed with a piece of equipment called a square baler, such as, a John Deere 346 Series Baler. A square baler machine, attached to a tractor or similar farm vehicle, gathers and bales fresh cut grass for storage and later use. To keep the bales from falling apart during subsequent handling and storage, the bales are wrapped with twine as they are formed. The twine wrapping and baling operation are synchronized to the amount of grass constituting the size of a finished bale. The baler machine includes a twine spool or reel that feeds twine to and wraps it around the bales, and is then held for tying and cutting in a twine holding disk. After a pre-selected amount of grass or hay is bundled, a twine cutting knife severs the twine allowing the bale to be released from the baler before another bale is formed. Typically the twine knife is mounted on a pivot arm that rotates against the twine holding reel when the twine is cut.
Twine used in the baling process is now made with advanced polymer materials that provide great strength to ensure the integrity of the finished bale. However, this type of twine is more difficult to cut. The inability to cut the twine fully and cleanly after completion of a baling cycle creates a wide variety of problems. Usually the worker must get off the tractor and manually sever the twine. This results in wasted twine as well as wasted time. When the twine is not completely cut, the finished bale may not be properly released from the baler and the moving parts of the baler may be subjected to undue strain. This often results in damage to the baler itself, such as jamming the moving parts, causing mechanical breakdown of the baler.
Many twine cutters used on conventional square balers use knives not designed to cut the modern twine materials. The twine often merely slides across the edge of the knife and slips off the end without completely cutting the twine, resulting in problems discussed above. Even when the twine is properly cut, the knives wear out relatively quickly when used in conjunction with the advanced polymer twines currently being used within the industry, requiring frequent knife replacement.
Prior art blade structures are disclosed in the following patent art. U.S. Pat. No. 2,204,475 to Crandall discloses a knife blade for use with a winding machine. The knife may have either a solid or serrated cutting edge. U.S. Pat. No. 4,995,216 to Vansteelant discloses a bale wrapping control apparatus having a serrated knife. U.S. Pat. No. 5,349,806 to Swearingen et al discloses a wrapping machine for round balers. The twine knife includes a serrated blade that cleanly severs the free end from the twine supply. U.S. Pat. No. 5,709,143 to Bentley discloses a round bale, twine cutter having a steel knife. U.S. Pat. No. 5,878,498 to Mundt discloses a steel tool for cutting bale twine.
However, these blade structures are used in very different environments than the knives employed in the use of square balers, such as, the John Deere 346 Series Balers. As the problems encountered are very different, the disclosures are not believed to address the problems currently encountered in the use and operation of square balers. For example, square balers are from time to time, and under certain circumstances, confronted with sap build-up problems not commonly encountered in other types of balers. In addition, the orientation of the various components in square balers is different from other baler types, necessitating different considerations in component design.
As such, a need exists for an improved tissue cutting apparatus for a square baler apparatus. The present invention provides such an apparatus.